Green analytical methodology for grape juice classification using FTIR spectroscopy combined with chemometrics

Abstract

The viticulture industry requires continuous control of production from the beginning of the maturation of the grapes to the bottling of the final product, in order to guarantee the safety and suitability of food. The development of methods that follow the concept of Green Analytical Chemistry (GAC) based on the principles of sustainability with less environmental impact aimed at differentiating organic from conventional grape juice is an important challenge in order to protect the consumer from possible marketing fraud. In this study, we explored a methodology that has been the advantages of minimal sample preparation, no use of solvents and without waste generation. The use of mid-infrared spectral data combined with chemometric procedures proves to be an attractive tool due to the fast, simplicity of operation, in addition the accuracy and reliability of the algorithms. The main spectral information was selected through genetic (GA), stepwise (SW), ant colony optimization (ACO) and successive projection (SPA) algorithms for use in building classification models using linear discriminant analysis (LDA). The dataset proved to be quality and robust due to its ability to be applied in different classification methods supervised by discriminant analysis (LDA and PLS-DA). The models presented excellent results of accuracy, sensibility and selectivity rates with 100% in the training and 100% test sets for the classes conventional and organic of grape juices. The selection of the most relevant wavenumbers by the models made it possible to distinguish regions of the spectrum that work as markers of functional groups that allow the identification and categorization of grape juice samples as organic and conventional produced in Brazil.

Keywords

• Green analytical methodology
• FTIR spectroscopy
• Grape juice
• Categorization
• Production system
• Chemometrics